1. Field of the Invention
The invention relates to an X-ray CT system, such as a multislice X-ray CT system, dual X-ray CT system, or cone beam X-ray CT system, for imaging a sectional plane of an inspection target object, and a method of manufacturing an X-ray CT system.
2. Description of the Related Art
With reference to FIG. 7, an X-ray CT system operates as follows. X-ray beams radiated from an X-ray tube are reduced by a collimator into fan-shaped or cone-shaped X-ray beams. Then, the X-ray tube and arcuate collimator and detector (array) arranged opposite to the X-ray tube are rotated about the inspection target object placed in an imaging region, X-ray information transmitted through the inspection target object is detected by the detector, and a signal of the information is processed by a computer, thereby obtaining an X-ray tomograph. X-ray beams radiated from the X-ray tube are of a type that transmits through the inspection target object and a type that scatters through the inspection target object. The collimator is provided in front of the detector to take only the transmitted X-ray information, to remove scatter beams diagonally entering, and to prevent crosstalk from occurring there between. In the collimator, X-ray shield plates are formed of a material less transmissive of X-rays, in correspondence to respective channels, in front of the detectors one-dimensionally or two-dimensionally arranged.
With reference to FIG. 8, the collimator includes an upper support 10, a lower support 12, side columns 16, and an abutment plate 14. These constituent members are independently, preliminarily grooved on the upper support, the lower support and the abutment plate. These grooves allow the insertion of the X-ray shield plates after assembly of the constituent member. The X-ray shield plates are inserted into the grooves of the collimator assembled after grooves are formed in units of the constituent members (see Jpn. Pat. Appln. KOKAI Publication No. 10-5207).
In this case, a step of aligning the grooves in a several hundreds of portions, which are provided to the respective constituent members, is necessary. According to the above-described collimator and a method of manufacturing an X-ray CT system, the groove alignment has to be done on the order of several tens of micrometers, and the number of the portions is as large as several hundreds. Further, grooving is done independently in units of the constituent members, so that it takes much processing time. In addition, the respective constituent members are manufactured in the manner that grooves are formed on a planar plate, and the plate is bent into the arcuate shape. As a result, however, a rectangular groove shape is deformed into a wedge shape, making it difficult to insert the X-ray shield plate into the groove. Even when processing is done to increase insertability, an inconvenience still occurs in that looseness or rattle occurs in a deep portion of the groove.